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Full text of "IS 15505: Gaseous Fire Extinguishing Systems--HCFC Blend A Extinguishing Systems"

**************** 




Disclosure to Promote the Right To Information 

Whereas the Parliament of India has set out to provide a practical regime of right to 
information for citizens to secure access to information under the control of public authorities, 
in order to promote transparency and accountability in the working of every public authority, 
and whereas the attached publication of the Bureau of Indian Standards is of particular interest 
to the public, particularly disadvantaged communities and those engaged in the pursuit of 
education and knowledge, the attached public safety standard is made available to promote the 
timely dissemination of this information in an accurate manner to the public. 




Mazdoor Kisan Shakti Sangathan 
'The Right to Information, The Right to Live'' 



Jawaharlal Nehru 
'Step Out From the Old to the New" 



IS 15505 (2004, Reaffirmed 2010) : Gaseous Fire 
Extinguishing Systems--HCFC Blend A Extinguishing Systems. 
ICS 13.220.10 



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Satyanarayan Gangaram Pitroda 
Invent a New India Using Knowledge 



Bhartrhari — Nitisatakam 
"Knowledge is such a treasure which cannot be stolen" 





FiEAFFSRa^ED 



18 15505:2004 

Mm 3Tf^ W^ Mc^frl4l - TT^R?ii^^T)# 

Indian Standard 
GASEOUS FIRE EXTINGUISHING SYSTEMS - 



HCFC BLEND A EXTINGUISHING SYSTEMS 



ICS 13.220.10 



©BIS 2004 

BUREAU OF INDIAN STANDARDS 

MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG 
NEW DELHI 110002 

September 2004 Price Group 7 



Fire Fiohtiiis, Sectional Committee, CED 22 



FOREWORD 

This Indian Standard was adopted by the Bureau of Indian Standards, after the draft finalized by the Fire 
Fighting Sectional Committee had been approved by the Civil Engineering Division Council. 

It is important that the fire protection of building or plant be considered as a whole. HCFC blend A total 
flooding systems form only a part, though an important part, of the available facilities. However, it should not 
be assumed that their adoption necessarily removes the need to consider supplementary measures, such as the 
provision of portable fire extinguisher or mobile appliances for first air or emergency use, or measures to deal with 
special hazards. 

HCFC blend A is recognized as effective for extinguishing Class A and Class B fires where electrical risks 
are present. Nevertheless, it should not be forgotten in the planning of the comprehensive schemes that there 
may be hazards for which this technique is not suitable, or that, in certain circumstances or situation, there may 
be danger in its use, requiring special precautions. Advice on these matters can be obtained from organizations 
involved with the installation of HCFC blend A total flooding systems. 

System in complete shall be approved by any recognized/independent authority. Agent dump/discharge test 
be replaced by enclosure integrity test unless required by legal requirement. 

For the purpose of deciding whether a particular requirement of this standard is complied with, the final 
value, observed or calculated, expressing the result of a test or analysis, shall be rounded off in accordance with 
IS 2 : 1960 'Rules for rounding off numerical values ( revised )\ The number of significant places retained in 
the rounded off value should be the same as that of the specified value in this standard. 



IS 15505 : 2004 



Indian Standard 

GASEOUS FIRE EXTINGUISHING SYSTEMS - 
HCFC BLEND A EXTINGUISHING SYSTEMS 



1 SCOPE 

1.1 This standard sets out specific requirements 
for the design and installation of total flooding 
fire-extinguishing systems employing HCFC blend A 
gas extinguishant. This standard is applicable to 
single supply as well as distributed supply 
systems. 

1.2 This standard complements various general 
requirements applicable to all types of gaseous 
fire-extinguishing systems ( Halocarbon as well as 
Inert gas systems ) listed in IS 15493. As such, both 
these standards should be read together before 
designing a system. Where requirements in both 
the standards differ, this standard shall take 
precedence. 

1.3 This standard covers total flooding systems 
of HCFC blend A operating at nominal pressures of 
2.5 MPa and 4.2 MPa only at 2 rC. 

2 REFERENCE 

The standard given below contains provisions which 
through reference in this text, constitute provisions 
of this standard. At the time of publication, the 
edition indicated was valid. All standards are 
subject to revision, and parties to agreements based 
on this standard are encouraged to investigate the 
possibility of applying the most recent editions of 
the standard indicated below: 



IS No. 



Title 



15493 :2004 Gaseous fire extinguishing 
systems — General requirements 

3 GENERAL INFORMATION 

3.1 Application 

3.1.1 HCFC blend A total flooding system is designed 
to develop a controlled atmosphere in an enclosed 
space and extinguishes the fires by cooling the flame 
and breaking the free radical chain reaction and 
thereby interfering with the combustion process. 
The appropriate HCFC blend A concentration 
shall also be maintained until the temperature 
within the enclosure has fallen below the re-ignition 
point. 

3.1.2 The minimum HCFC blend A concentration 
necessary to extinguish a flame has been determined 
by experiments for several surface-type fires 



particularly those involving liquids and gases. For 
deep-seated fires, longer soaking times may be 
necessary but are difficult to predict. 

3.1.3 It is important that concentrations are not 
only achieved but also maintained for a sufficient 
period of time to allow effective emergency action by 
trained personnel. This is equally important in all 
classes of fires since a persistent ignition source can 
lead to a recurrence of the initial event once the HCFC 
blend A has dissipated. 

4 GAS CHARACTERISTICS AND PROPERTIES 

4.1 HCFC blend A is a colourless, electrically non- 
conductive gas with a citrus like odour and with a 
density approximately three times that of air. 

4.2 HCFC blend A total flooding system can be 
used to extinguish all classes of fires. Information 
on use and limitations of HCFC blend A is available 
in IS 15493. 

4.3 HCFC blend A gas is a blend of various gases, 
the composition of which is as shown in Table 1 . 

4.4 HCFC blend A is a blend of gases liquefied at 
suitable pressure and temperature, that can be stored 
in a pressurized container. 

4.5 HCFC blend A gas shall comply with 
specification as shown in Table 2. The purity of 
HCFC blend A shall be determined in accordance with 
Annex A. 

4.6 Physical properties of HCFC blend A gas is 
shown in Table 3. 

4.7 Toxicological information for HCFC blend A gas 
are shown in Table 4. 

4.8 Container Characteristics 

The maximum fill density, container working 
pressure of the HCFC blend A cylinders shall not 
exceed the values provided in Table 5 for systems 
operating at 2.5 MPa and 4.2 MPa respectively, 

NOTES 

1 For further data on pressure/temperature 
relationship, Fig. 1 and Fig. 2 shall be referred. 

2 Exceeding the maximum till density may result in 
the container becoming liquid full. With the result that 
an extremely high rise in pressure occurs with small 
increases in temperature that could adversely affect the 
integrity of the container assembly. 



IS 15505:2004 



Table 1 Composition of HCFC Blend A Gas 

(Clauses 43 and k-\ ) 



SI No. 


Clean Agent 
Formulae 


Chemical Name 


Commercial Name 


Tolerance 
( Percent by Mass ) 


(1) 


(2) 


(3) 


(4) 


(5) 


i) 


CHCi^CFj 


Dichloro trifluoro ethane ^ 
(HCFC- 123, 4.75 percent) 




±0.5 


ii) 
iii) 


CHCIF2 
CHCIFCF3 


Chloro difluoro methane 
( HCFC - 22, 82 percent ) 

Chloro tetrafluoro ethane 
( HCFC- 124, 9.5 percent) 


HCFC blend A 


± 0.8 
±0.9 


iv) 


{ Detoxifier) 


Iso proponyl-1 -methyl cycol- 
hexane ( 3.75 percent ) 




±0.5 



Table 2 Specification for HCFC Blend A Gas 

{Clause A, 5) 



SI No. Property 

(1) (2) 

i) Purity 

ii) Moisture 

iii) Acidity 

iv) Non-volatile residue 

v) Suspended matter or 
sediment 



Requirement 

(3) 
99.6 percent by mass, Min 
1 X 1 0"^ by mass, Max 
3 X 10"^ by mass, Max 
0.01 percent by mass, Max 
None visible 



Table 3 Physical Properties 

( Clause 4.6 ) 



SI No. Property 

(1) (2) 

i) Molecular mass 

ii) Boiling point at 0.1 MPa 

iii) Freezing point 

iv) Vapour pressure at 20°C 

v) Specific volume of super- 
heated vapour at 1 bar 
and 20°C ( mVkg ) 

vi) Critical temperature 

vii) Critical pressure 

viii) Critical volume 

ix) Critical density 

x) Liquid density at 20°C 

xi) Saturated vapour density 
at 20"C 



Value 

(3) 
92.9 
-38.3°C 
<-107.2^C 
825 kPa 
0.259 

125°C 
6.65 MPa 
170 cm^/mol 
580 kgW 
1 200 kg/m^ 
31 kg/m^ 



4.9 Pressure v^r5W5 Temperatures 

To allow faster flow through piping systems, the 
natural pressure of HCFC blend A is often 
supplemented with dry nitrogen. Commonly used 
pressures are respectively 2.5 MPa and 4.2 MPa 
measured at 21°C. The respective vapour pressures 



Table 4 Toxicological Information 

[Clauses4n,53 andlA{d)] 

SI No. Property Value 

(1) (2) (3) 

i) No observed adverse effect level 10 percent 
( NOAEL ) 

ii) Lowest observed adverse effect > 10 percent 
level ( LOAEL ) 

iii) 4 hour lethal concentration LC5Q 64 percent 

Table 5 2.5 and 4.2 MPa Storage Container 
Characteristics for HCFC Blend A 



{Clause 4.8) 



SI No. Property 

(1) (2) 

i) Maximum fill density 
900 kg/m^ 

ii) Maximum container work- 
ing pressure at 55'*C 

iii) Superpressurization at 
20°C 



'2.5 MPa 

(3) 

0.9 kg 

( litre) 

3.5 MPa 



Value 



4.2 MPa 

(4) 

0.9 kg 
(litre) 

5.3 MPa 



2.5 MPa 4.2 MPa 



of HCFC blend A as well as dry nitrogen vary with 
temperature. 

4.10 Nitrogen Superpressurization 

Nitrogen is soluble in HCFC blend A. Thus when a 
storage cylinder is pressurized with nitrogen, some 
dissolves in the liquid HCFC blend A and the rest 
remains in the vapour phase and combines with the 
vapour pressure of HCFC blend A to produce the 
pressure necessary to propel the HCFC blend A 
through the pipeline ( see Fig, 1 ). 

5 SAFETY OF PERSONNEL 

5.1 Any hazard to personnel created by the discharge 
of HCFC blend A shall be considered in the design 



IS 15505 : 2004 



CO 

2 3 

111 

CO 

m 2 



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-" 










% 








h 








— 


' 








._^ 










^ . 







"^ 































-50 -40 -30 -20 -10 10 20 30 40 50 60 

TEMPERATURE. X 

Fig. 1 Pressure/Temperature Curves OF HCFC Blend A 



CO 

E 
ui 

:^ 

13 
_j 

o 
> 

a: 

o 

Q. 

o 



o 

LU 
Q- 
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0.35 






















































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0.3U 


^ 




























^ 




— 




1 
















1 






U.2b 
















-^ 


-^ 






































0.2U 














r — 












































0.1b 




























































U.1U 




























































0.05 





























































-5 





-4 





-3 





-2 





-1 





. < 


) 


■ 1 




A 


2 





3 




1] 


'.^ 




A 


5 





■.^ 





.^ 




7 


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ft 


9 


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45 -35 -25 -15 -5 



5 

TEMPERATURE. X 



Fig. 2 Specific Volume of Superheated HCFC Blend A Vapour at Sea Level 

3 



IS 15505: 2004 



of the system. Potential hazard can arise from the 
following: 

a) Extinguishant itself, 

b) Combustion products of the fire, and 

c) Breakdown products of the extinguishant 
resulting from exposure to fire. 

5.1.1 In areas, where there is a likelihood of significant 
differences between gross and net volumes of the 
enclosure, utmost care shall be exercised in proper 
system design to ensure that maximum concentrations 
as given in 5.1(c) are not exceeded. 

5.2 Where the design concentration exceeds the 
LOAEL, HCFC blend A shall be used only for total 
flooding in normally unoccupied areas. For minimum 
safety requirements, provisions laid down in 5 of 
IS 15493 shall be followed. 

5.3 Toxicological information of HCFC blend A is 
given in Table 4. 

5.4 Miscellaneous Hazards 

Some of the additional hazards are as below: 

a) Cold temperatures — Direct contact with 
the vapourizing liquid being discharged 
from a HCFC blend A system will have a 
strong chilling effect on objects and can 
cause frostbite burns to the skin. The liquid 
phase vapourizes rapidly when mixed with 
air and thus limits the hazard to immediate 
vicinity of the discharge point. 

b) Visibility — Discharge of HCFC blend A 
may create a light mist resulting from 
condensation of moisture in the air. 
However, the mist rarely persists after the 
discharge is completed. Thus little hazard 
is created from the standpoint of reduced 
visibility. Once HCFC blend A is discharged 
into an enclosure, its presence is easy to 
detect through the normal senses in 
concentrations above about 3 percent. 

c) Uneven distribution — In total flooding 
systems, the high density of HCFC blend A 
vapour requires the use of discharge 
nozzles that will achieve a well-mixed 
atmosphere in order to prevent local 
pockets of higher concentration. HCFC 
blend A and HCFC blend A air mixtures are 
also more dense than air and will drift and 
accumulate in low spaces, such as cellars, 
pits and floor voids, and may be difficult to 
ventilate effectively. 

6 VENTING ARRANGEMENT 

Venting shall be provided at levels as high as possible 



in the enclosure. Allowable pressures for average 
enclosures shall be in conformity with the following 
guidelines. The building requirements for the type 
of enclosure and free venting required can also be 
calculated from the relevant specifications. 

7 EXTINGUISHING AGENT SUPPLY 

7.1 Quantity 

a) Quantity requirements ( main ) — The 
amount of the HCFC blend A in the system 
shall be at least sufficient for the largest 
single hazard protected or group of 
communicating hazards that are to be 
protected simultaneously. 

b) Quantity requirements (reserve) — Where 
required, the reserve quantity should be 
same as that of main supply as in 7.1(a). 
However if replenishing of HCFC blend A 
gas supply takes more than 7 days at the 
site of installation, advice may be sought 
from the authority concerned on the quantity 
to be kept available as reserve. 

c) Uninterrupted protection — Where 
uninterrupted protection is required, 
reserve supply and main supply should be 
permanently connected to the distribution 
piping and arranged for easy changeover to 
enable uninterrupted protection. 

d) The quantity of the HCFC blend A required 
shall be further adjusted to compensate for 
any special conditions, such as unclosable 
openings, forced ventilation, the free 
volume of air receivers that may discharge 
into the risk, altitude ( substantially above 
or below sea level ) or any other causes for 
the extinguishant loss. However in no 
case the injected concentration of the 
HCFC blend A gas shall exceed its LOAEL 
(^ee Table 4). 

7.2 Total Flooding Quantity 

All HCFC blend A total flooding systems shall be 
capable of producing the required concentration under 
the conditions of maximum net volume, maximum 
leakage and minimum expected ambient temperatures. 
Fig. 2 shows the specific volume of superheated HCFC 
blend A vapour at various temperatures. 

a) The amount of HCFC blend A required to 
achieve the design concentration shall be 
calculated from the following equations 
and this figure shall need further 
adjustment as stated in 7. 1(d): 



M = 



VC 



5(100-C) 



IS 15505 : 2004 



where 
M 
C 



total flooding quantity, kg; 

design concentration, percent by 
volume; 

net volume of the hazard, m^; 

K^+ K^iT), where K^ and K^ are constants 
specific to the agent used and Tis minimum 
temperature inside enclosure; and 

specific volume of superheated agent at 
2PC,m%g. 

Specific volume constants for the HCFC blend 
A gas are K^ - 0.241 3 and K^ = 0.000 88. It may 
also be noted that this equation provides an 
allowance for the normal leakage from a tight 
enclosure to accomplish equalization of pressure. 



V 

S 



b) The agent requirement per unit volume of 
protected space can also be calculated by 
using Table 6 for various levels of 
concentration corresponding to the 
temperature within the protected enclosure 
( flooding factor obtained from Table 6 that 
is temperature of the enclosure versus gas 
concentration, multiplied by net volume of 
the enclosure ). 

NOTE — Quantity of the agent shall be the highest of 
the values calculated from the provisions contained in 
7.2(a) and 7.2(b), 

7.3 The actual quantity of HCFC blend A gas storage 
required shall be determined in the following manner, 
which shall further be subject to changes for pressure 
due to elevation [ see 8(g) and Table 8 ]. 



Table 6 Total Flooding Quantity ( HCFC Blend A ) 

[Clause 12(b)] 



SI 


Tempera- 


Specific 




HCFC Blend A Mass Requirements per 


Unit Veil 


ime of Protected 


1 


No. 


ture 


Vapour 










Space 


( kg/m^ ) 












T 


Volume, S 




Design Concentration 


by Volume, C, Percent 








T 


m^/kg 


r 

1 


8 


9 


10 


11 


12 


13 


14 


15 


16 


(1) 


(2) 


(3) 


(4) 


(5) 


(6) 


(7) 


(8) 


(9) 


(10) 


(11) 


(12) 


(13) 


i) 


-35 


0.210 


0.358 


0.413 


0.470 


0.528 


0.588 


0.648 


0.710 


0.774 


0.839 


0.906 


ii) 


-30 


0.215 


0.351 


0.405 


0.461 


0.517 


0.576 


0.635 


0.696 


0.758 


0.822 


0.887 


iii) 


-25 


0.219 


0.343 


0.397 


0.451 


0.507 


0.564 


0.622 


0.682 


0.743 


0.805 


0.869 


iv) 


-20 


0.224 


0.337 


0.389 


0.442 


0.497 


0.553 


0.610 


0.668 


0.728 


0.790 


0.852 


V) 


-15 


0.228 


0.330 


0.381 


0.434 


0.487 


0.542 


0.598 


0.655 


0.714 


0.774 


0.835 


vi) 


-10 


0.232 


0.324 


0.374 


0.426 


0.478 


0.532 


0.587 


0.643 


0.700 


0.760 


0.819 


vii) 


-5 


0.237 


0.318 


0.367 


0.418 


0.469 


0.522 


0.576 


0.631 


0.687 


0.745 


0.804 


viii) 





0.241 


0.312 


0.360 


0.410 


0.461 


0.512 


0.565 


0.619 


0.675 


0.731 


0.789 


ix) 


5 


0.246 


0.306 


0.354 


0.403 


0.452 


0.503 


0.555 


0.608 


0.663 


0.718 


0.775 


X) 


10 


0.250 


0.301 


0.348 


0.396 


0.444 


0.494 


0.545 


0.598 


0.651 


0.706 


0.762 


xi) 


15 


0.254 


0.296 


0.342 


0.389 


0.437 


0.486 


0.536 


0.587 


0.640 


0.693 


0.748 


xii) 


20 


0.259 


0.291 


0.336 


0.382 


0.429 


0.477 


0.527 


0.577 


0.629 


0.682 


0.736 


xiii) 


25 


0.263 


0.286 


0.330 


0.376 


0.422 


0.469 


0.518 


0.568 


0.618 


0.670 


0.723 


xiv) 


30 


0.268 


0.281 


0.325 


0.369 


0.415 


0.462 


0.509 


0.558 


0.608 


0.659 


0.711 


xv) 


35 


0.272 


0.277 


0.320 


0.363 


0.408 


0.454 


0.501 


0.549 


0.598 


0.648 


0.700 


xvi) 


40 


0.277 


0.272 


0.314 


0.358 


0.402 


0.447 


0.493 


0.540 


0.589 


0.638 


0.689 


xvii) 


45 


0.281 


0.268 


0.310 


0.352 


0.395 


0.440 


0.485 


0.532 


0.579 


0.628 


0.678 


xviii) 


50 


0.285 


0.264 


0.305 


0.347 


0.389 


0.433 


0.478 


0.524 


0.570 


0.616 


0.667 


xix) 


55 


0.290 


0:260 


0.300 


0.341 


0.383 


0.427 


0.471 


0.516 


0.562 


0.609 


0.657 


xx) 


60 


0.294 


0.256 


0.296 


0.336 


0.378 


0.420 


0.463 


0.508 


0.553 


0.600 


0.647 


xxi) 


65 


0.299 


0.252 


0.291 


0.331 


0.372 


0.414 


0.457 


0.500 


0.545 


0.591 


0.638 


xxii) 


70 


0.303 


0.248 


0.287 


0.326 


0.367 


0.408 


0.450 


0.533 


0.537 


0.582 


0.628 


xxiii) 


75 


0.307 


0.245 


0.283 


0.322 


0.361 


0.402 


0.444 


0.436 


0.529 


0.573 


0.620 


xxiv) 


80 


0.312 


0.241 


0.279 


0.317 


0.356 


0.396 


0.437 


0.479 


0.522 


0.566 


0.611 


xxv) 


85 


0.317 


0.238 


0.275 


0.313 


0.351 


0.391 


0.432 


0.472 


0.515 


0.558 


0.602 


xxvi) 


90 


0.321 


0.235 


0.271 


0.308 


0.346 


0.385 


0.425 


0.456 


0.508 


0.550 


0.594 


xxvii) 


95 


0.225 


0.232 


0.267 


0.304 


0.342 


0.380 


0.419 


0.450 


0501 


0.543 


0.586 



IS 15505 : 2004 



7.3.1 Enclosure Volumes 

The net enclosure volumes are calculated using the 
following equations: 



y = y _y 
^ Max g '^ s' 



a) 



where 



V. 



Max 



Min 



maximum net volume of the 
enclosure, m^; 

gross volume of enclosure, 
m^; 

volume of the structural/similar 
permanent objects in the 
enclosure that gas can not 
permeate, m^; 

minimum net volume of 
enclosure considering the 
maximum anticipated volume 
of the occupancy related to 
the objects in the enclosure, 
m^; and 

F^ = volume of the occupancy 
related objects in the enclosure 
that gas can not permeate, for 
example, furniture fittings, 
etc, in m^ ( This value shall be 
ignored if that volume is less 
than 25 percent of the maximum 
net volume F^^ J. 

8 DESIGN CONCENTRATION 

a) Determination of design concentration of 
HCFC blend A shall include consideration 
of the type and quantity of combustibles 
involved, the conditions under which it 
normally exists in the enclosure, and any 
special conditions in the enclosure. The HCFC 
blend A system design shall be capable of 
establishing uniform design concentration 
throughout the protected volume. 

b) The distribution system for applying 
HCFC blend A to enclosed hazards shall be 
designed with due consideration of the 
materials involved, the type of burning 
expected and the nature of the enclosure, 
anyone of which may affect the discharge 
times and rates of application. 

c) The minimum design concentration of 
HCFC blend A for fires involving surface class 
A, and also fires involving flammable liquids 
and gases shall be as follows: 

1) The minimum design concentration of the 
HCFC blend A agent for Class A surface 
fire hazards shall be the extinguishing 



concentration ( 7.2 percent ) plus a 
loading of 20 percent as a safety factor. 

2) The minimum design concentration of the 
HCFC blend A agent for Class B ftre 
hazards shall be the extinguishing 
concentration ( 7.2 percent ) with a 
loading of 30 percent as a safety factor. 

NOTE — Where different classes of 
hazards exist, design concentration 
shall be for the hazard requiring the 
greatest concentration. 

d) Requirements for flame extinguishment — 
Tests shall be conducted in independent 
recognized laboratories for the determination 
of extinguishing concentration. This value 
as determined shall be loaded by a safety 
factor of 30 percent. In no case, shall the design 
concentration be less than Z,6 percent or such 
higher figure, determined by test as indicated 
above. 

e) Requirements for inerting 

1) Minimum concentration requirements 
for inerting atmospheres within the 
enclosure involving flammable liquids 
and gases shall be as shown in Table 7. 
Where range of separate fuels is present, 
the inerting concentration shall be as 
shown in Table 7 for the fuel requiring 
the greatest concentration. 

2) For other fuels not listed in the Table 7, 
tests shall be conducted in independent 
recognized laboratories for the 
determination of inerting concentration. 
This value as determined from Table 7 
shall be loaded by a safety factor of 
10 percent. In no case, shall the 
inerting concentration be less than 8.6 
percent or such higher figure, 
determined by test as indicated above. 

f) Lastly, it is required to adjust the number of 
HCFC blend A agent containers, where 
necessary, by compensating for ambient 
pressure change due to location elevation 
as per 8(g) and round off the number as 
before. The equation in such cases will be 
as follows: 

N^ = TV times atmospheric correction factor 

where 

yVj = adjusted number of containers, and 

N = initial number of containers. 

g) Atmospheric correction factors — It shall 
be necessary to adjust the actual HCFC blend 
A agent quantity for altitude effects. 
Depending upon the altitude, atmospheric 



IS 15505 : 2004 



correction factor shall be applied as per 
Table 8. The adjusted HCFC blend A 
agent quantity is determined by 
muhiplying the number of HCFC blend A 
containers by the ratio of average ambient 
enclosure pressure to standard sea level 
pressure. 

Table 7 HCFC Blend A Design Concentration 
for Inerting 

[ Clause 8(e) ] 



SI No. 


Material 


Percentage 
by Volume 


(1) 


(2) 


(3) 


i) 


Acetone 


12.0 


ii) 


Benzene 


12.5 


iii) 


Methane 


18.6 


iv) 


/?- Heptane 


13.0 


V) 


Propane 


18.3 


vi) 


Mythyl ethyl ketone 


14.0 


vii) 


Iso-butane 


18.4 


viii) 


Difluoromethane ( HFC32 ) 


8.6 



Table 8 Atmospheric Correction Factors 

[ Clauses 7.3 and 8(g) ] 



SI No. 


Equivalent 


Enclosure 


Atmospheric 




Altitude 


Pressure 


Correction 




m 


mmHg 


Factor 


(1) 


(2) 


(3) 


(4) 


i) 


-920 


840 


1.11 


ii) 


-610 


812 


1.07 


iii) 


-300 


787 


1.04 


iv) 





760 


1.00 


V) 


300 


733 


0.96 


vi) 


610 


705 


0.93 


vii) 


920 


678 


0.89 


viii) 


1 220 


650 


0.86 


ix) 


1 520 


622 


0.82 


X) 


1 830 


596 


0.78 


xi) 


2 130 


570 


0.75 


xii) 


2 440 


550 


0.72 


xiii) 


2 740 


528 


0.69 


xiv) 


3 050 


505 


0.66 



9 APPLICATION RATE, DURATION OF 
DISCHARGE AND DISCHARGE TIME 

9.1 Design Application Rate 

The design application rate shall be based on the 
quantity of HCFC blend A (Af^) as per 8(c) and the 
duration of discharge required under 9.2. 



9.2 Duration of HCFC Blend A Discharge 

The minimum theoretical injected concentration shall 
be achieved within 10 s and the actual injected 
concentration ( that is the above plus a suitable safety 
factor adjusted for container rounding off) shall be 
achieved within 2 min. 

9.3 Discharge Time for the HCFC Blend A Gas 

The discharge time shall be the time for actuation of 
the first HCFC blend A container valve to the 
achievement of the required design concentration or 
the discharge time is the interval from the first 
appearance of liquid at the nozzle to the time when 
the discharge becomes predominantly gaseous, 
recognized by a change in the appearance and sound 
of the discharge. 

a) The discharge time period is defined as the 
time required to discharge from the nozzles 
90 percent of the agent mass at 21 °C, 
necessary to achieve the minimum design 
concentration based on a 20 percent safety 
factor for flame extinguishment, 

b) The discharge time required to achieve 
95 percent of the minimum design 
concentration for flame extinguishment based 
on a 20 percent safety factor shall not exceed 
10 s, and 

c) Flow calculations performed in accordance 
with 12, or in accordance with the approved 
pre-engineered systems, shall be used to 
demonstrate the discharge time requirements 
stated above. 

10 STORAGE CONTAINERS 

10.1 The HCFC blend A storage containers shall 
comply with the following in addition to various 
requirements contained in IS 15493. 

10.1.1 The containers used in HCFC blend A systems 
shall be seamless cylinders designed, fabricated, 
inspected, certified and stamped in accordance with 
the requirements of Chief Controller of Explosives, 
Nagpur. 

10.1.2 The design pressure shall be suitable for the 
maximum pressure developed at SS^'C or at the maximum 
controlled temperature limit. 

10.1.3 The containers shall be charged to a filling 
ratio ( fill density ) not greater than 900 kg/m^ and 
not less than 500 kg/m^. 

10.1.4 The containers shall be superpressurized 
with nitrogen (moisture content not greater than 
0.005 percent by volume) to a total pressure of 
either 2.5 MPa± 5 percent or at 4,2 MPa± 5 percent 
measured at21 ± 1°C. 



IS 15505 : 2004 



1 0.1.5 The storage containers shall have reliable means 
of indicating their pressure. 

10.1.6 The storage containers shall have reliable 
means of indicating the variation of container 
pressure with temperature. A pressure/temperature 
chart ( see Fig. 3 ) attached to the container, is 
acceptable. 

10.1.7 The requirements of authorities having 
jurisdiction for containers may take precedence 
over the requirements of this standard, if their 
specifications are more stringent. 

11 DISTRIBUTION SYSTEM 

The HCFC blend A distribution system shall 
comply with the following in addition to various 
requirements contained in IS 15493. 

11.1 Piping Network 

a) The piping shall withstand the maximum 
expected pressure at the maximum storage 
temperature, as follows: 

1) 2.5MPasystems:4.19MPaat55X 

2) 4.2 MPa systems: 6.58 MPa at 55°C 

b) The piping shall withstand the maximum 
developed pressure at 55''C and shall be in 



accordance with IS 15493. 

c) Carbon steel pipes and fittings shall be 
galvanized inside and outside or otherwise 
suitably protected against corrosion. 
Stainless steel pipes and fittings may be used 
without corrosion protection. 

NOTE — Stainless steel pipes may be used in all 
applications subject to appropriate design strength 
calculations. 



11.2 Piping Fittings 



the 



a) Pipe fittings shall comply with 
requirements given in IS 1 5493 . 

b) Fittings shall be selected according to the 
wall thickness or schedule number of the pipe 
to which they are intended to be fitted. 

11.3 Pipe Sizing 

Pipe sizing is a complex issue, particularly in view of 
the two-phase flow within the pipelines. Too small a 
bore results in excessive pressure losses while too 
large a bore reduces the liquid flow velocity. This also 
may result in excess pressure drops and lower flow 
rates. Table 9 may be used as a guide to estimate pipe 
sizes. The sizes can be checked using an approved 
computer flow calculation programme. 





4.D 

4.0 


- 
















/ 


/ 




- 














/ 


/ 






3.5 


- 












J 


/ 






\n 

D 
CO 

if) 
us 
a: 

Ql 


3.0 
2.5 

2.0 


- 












/ 








- 








y 


/ 


f 








- 




/ 


/ 


/ 














- 


y 


/ 


















1 *; 


Mil 


Mil 


nil 


nil 


Hit 


nil 


nil 


ini 


nil 


nil 



o.o 


- 


















/ 


6.0 


- 


















/ 


- 
















/ 




5.5 


- 
















/ 




_ 














/ 






Q. 

:i 

^-5.0 

D 

CO 

^ 4.5 


- 














/ 






- 










> 


/ 








- 










/ 










4.0 


- 








y 












- 






y 


/ 












3.5 


- 




/ 


r 














_ 




/ 
















3.0 


> 


y 


















_x 




















9 R 


Till 


nil 


nil 


nil 


nil 


WW 


nil 


nil 


nil 


WW 



-30 -20-10 10 20 30 40 50 60 70 
TEMPERATURE. °C 



-30 -20 -10 10 20 30 40 50 60 70 
TEMPERATURE. X 



(a) 2.5 MPa nominal fill at 15X (b) 4.2 MPa NOMINAL FILL AT 15X 

Fig. 3 Temperature/Pressure Variations for HCFC Blend A in Storage Containers 



IS 15505 ! 2004 



Table 9 Pipe Sizes versus Flow Rate ( Informative ) 

{Clause \\ 3) 



SI No. 


Nominal Bore 


Minimum Flow 


Maximum 


Flow Rate for Equiva 


ilent Lengths 




mm 


Rate, kg/s 




of Pipe, kg/s 






More Than 


Between 


Up to 5 m 








10 m 


5 and 10 m 




(1) 


(2) 


(3) 


(4) 


(5) 


(6) 





10 


0.3 


0.3 


0.4 


0.5 


ii) 


15 


0.5 


0.5 


0.7 


1.0 


iii) 


20 


1.0 


1.0 


1.0 


2.0 


iv) 


25 


1.5 


1.5 


2.7 


4.0 


V) 


32 


2.6 


3.5 


5.6 


8,0 


vi) 


40 


3.8 


4.5 


8.6 


12.2 


vii) 


50 


5.9 


8.8 


16.3 


23.5 


viii) 


65 


8.8 


14.5 


25.4 


37.0 


ix) 


80 


15.0 


25.0 


45.0 


63.5 


X) 


100 


26.3 


50.0 


90.0 


131.5 


xi) 


125 


43.0 


95.0 


172.0 


250.0 


xii) 


150 


57.5 


150.0 


272.0 


408.0 



11.4 Nozzle Placement 

a) The type of nozzles selected, their number 
and placement shall be such that the design 
concentration will be established in all parts 
of the protected enclosure and such that the 
discharge will not unduly splash flammable 
liquids or create dust clouds that could extend 
the fire, create an explosion, or otherwise 
adversely affect the contents or the integrity 
of the enclosure. 

b) Selecting the number of nozzles in a system 
shall take into account, the shape of the 
enclosure ( area and volume ), shape of the 
void ( raised floor, suspended ceiling ), 
installed equipment in the enclosure/void 
( chimney effect ), allowed pressure at the 
restrictor ( Pipe quality ) and obstructions, 
which may affect the distribution of the 
discharged agent and architectural 
considerations. 

c) Nozzles shall be selected and located to protect 
an area less than its area of coverage. The 
area of coverage to the type of nozzle shall 
be so listed for the purpose. 

d) In hazards having suspended ceiling, 
consideration shall be given for having 
nozzles installed in the ceiling void 
( simultaneous discharge ) in order to equalize 
the pressure during discharge, thus reducing 
the risk of unnecessary damaging ceiling tiles 
etc. 

e) In hazards having raised floor ( not gas- 



tight ) consideration shall be given for 
having nozzles installed in the floor void 
( simultaneous discharge ) in order to 
equalize the pressure and obtain 
extinguishing concentration below the floor. 

f) In hazards having suspended ceiling, nozzles 
for protecting rooms shall be installed in such 
a way that the jets from the nozzles do not 
damage the ceiling plates excessively during 
discharge, that is, the nozzles to be positioned 
vertically with the discharge holes free of the 
ceiling tiles and/or Escutcheon plates. For 
light weight ceiling tiles, it may be 
recommended to securely anchor tiles for a 
minimum of 1 .5 m from each discharge nozzle. 

g) Maximum nozzle height above floor level for 
a single row of nozzles is 3 .5 m . Where ceiling 
height ( of the protected enclosure ) exceeds 
3.5 m, an additional row of nozzles shall be 
provided for uniform and faster distribution 
of the agent within the enclosure. 

h) Minimum nozzle height above the floor level 
of the hazard shall be 0.2 m. 

j) The maximum distance between nozzles should 
not exceed 6 m and the maximum distance to 
wall/partition should not exceed 3 m. 

k) In case of enclosures having no false ceiling, 
nozzles can be located on the ceiling anywhere 
within 0.5 to 5 m from the walls. In case of 
enclosures having false ceilings, deflector 
shields shall be used with each nozzle and 
also nozzles shall be so located ( with an 



IS 15505 : 2004 



anticipation of dislodgement of false ceiling 
materials or any movable objects in the path 
of discharge ) to prevent any damage thereto. 

Nozzles shall be provided in all the concealed 
spaces, floor voids, ceiling voids, etc, besides 
the main area within the protected enclosure. 

12 HYDRAULICS OF THE SYSTEM 

12.1 General 

a) An approved hydraulic calculation method 
shall be employed to predict pipe sizes, 
nozzle pressure, agent flow rate, discharge 
per nozzle and the discharge time. 

b) The various parameters as stated below shall 
be considered to determine the following 
minimum limits of accuracy: 

1) The weight of agent predicted by flow 
calculation to discharge from the nozzle 
should agree with the total weight of 
agent actually discharged from each 
nozzle in the system within a range of 
-5 to +10 percent of actual prediction. 

2) The discharge time predicted by the flow 
calculation method should agree with the 
actual discharge time from each nozzle 
in the system. 

3) The accuracy of the calculated nozzle 
pressures versus actual pressures at each 
nozzle should be such that actual nozzle 
pressures in an installation will not fall 
outside the range required for acceptable 
nozzle performance. 

4) The nozzle pressure should not fall below 
the minimum or above the maximum 
nozzle pressure required for the nozzle 
to uniformly distribute the agent 
throughout the volume and to protect 
nozzle's discharge. 

12.2 Two-Phase Flow ofHCFC Blend A 

The two-phase flow of HCFC blend A shall be in 
accordance to Annex B of IS 15493. 

12.3 Engineered and Pre-engineered Systems 

a) General — HCFC blend A is suitable for use 
in both engineered (central storage) systems 
and pre-engineered (modular or packaged) 
systems, as described in 12, 3(b) and 
12.3(c). 

b) Engineered — An engineered system 
uses large storage containers installed in a 
central location. The containers are manifold 
together and a single pipe feeds the nozzle 
located inside the hazard area. Predicting 



pipe pressure losses and designing nozzle 
orifice sizes requires complex flow 
calculations for both HCFC blend A and 
nitrogen phases, which takes into account 
the minimum and maximum volumes or the 
enclosure ( see Fig. 4 ). 

c) Pre-engineered — A pre-engineered system 
involves a single container with a maximum 
of two nozzles and a small piping network. 
This system can be multiplied to cover larger 
volume areas. The larger area is viewed as a 
number of smaller areas each protected by a 
single modular unit ( see Fig. 5 ). 

13 POST DISCHARGE SCENARIO 

The HCFC blend A system, when tested for discharge 
test, in accordance with the following requirements 
shall be: 

a) Within 1 min of commencement of discharge, 
the concentrations at not more than 1 m above 
the floor of the enclosure or at the top of the 
highest hazard shall not vary from the design 
concentration by more than 1 percent by 
volume. 

b) At 10 min of the discharge or other period 
( as required if necessary ), the concentrations 
at the levels given in 13(a) shall be not less 
than 80 percent of the design concentration 
( Retention time ). 

14 COMMISSIONING AND ACCEPTANCE 

TESTING 

14.1 Criteria for Acceptance 

The completed HCFC blend A total flooding 
system shall be commissioned in accordance with 
provisions of IS 15493 and the system's performance 
proved. 

14.2 Reporting 

The following shall be reported: 

a) Information identifying the system shall 
include: 

1) Installation, designer and contractor; 

2) Enclosure identifications; 

3) Enclosure temperature prior to 
discharge; 

4) Oxygen and carbon dioxide residual 
concentrations; and 

5) Positionof sampling points. 

b) Date and time of test. 

c) Discharge time. 



10 



IS 15505 : 2004 



d) Concentration levels at each sampling point 
at 2 min and 1 min from the commencement 



of discharge. 



e) System deficiencies. 

f) Reference to this test method in accordance 
with IS 15493. 



CEILING 
VOID 



CEILING VOID 
NOZZLES 




EXTINGUISHANT 
CONTAINERS 



Fig. 4 Typical Engineered HCFC Blend A System 



CEILING 
VOID 



INCLINED MODULES SUITABLE 
FOR FLOOR AND CEILING VOIDS 



CONTROL 
CIRCUIT 




ROOM 
NOZZLE 



LARGE 
CONTAINERS 



CONTROL 
CABINET 



SMALL CONTAINERS 
FOR LESS ACCESSIBLE 
AREAS 



Fig. 5 Typical Pre-engineered HCFC Blend A System 



11 



IS 15505 : 2004 



ANNEX A 

( Clause 4.5 ) 

DETERMINATION OF PURITY OF HCFC BLEND A 



A-1 HCFC blend A is a blend of three single 
HCFC components and a detoxifier as given 
in Table 1. A random sampling of 10 percent of the 
production is undertaken to determine the quality 
of the production. 

A-2 Following the filling of production cylinder, 
a 1 kg sample is removed from the selected cylinder 
and stored in a sampling cylinder. A small amount of 
HCFC blend A is expelled from the valve until the 
liquid phase of the product is produced. A 1 litre 
capacity polypropylene sampling bag is connected 
to the cylinder and 2 ml of the blend is drawn into the 
bag. It is essential that only liquid blend is allowed 
to be sampled. 

A-3 The bag together with the sample of blend is 
conditioned by placing in an oven at 40°C for 20 min 
in order to ensure that a homogeneous gasified 
sample is produced. A sample of 1 microlitre is injected 
into the column of the gas chromatograph 
equipment and analysed. The percentage of each 
HCFC component shall be determined from the 
resulting chromatograph by comparison with the 
standard graphs [ see Fig. 6(a) and 6(b) ]. The areas 
of the chromatograph are measured automatically, 



converted to a percentage. 

A-4 The use of G.C. technique does not provide a 
sufficiently accurate analysis result in respect of the 
detoxifier component and therefore an additional 
procedure is used to determine this parameter, using 
a simple weighing technique. 

A-5 The cylinder containing the remaining 
sample of blend ( after determining the HCFC 
content ) is weighed accurately to an accuracy of 
0. 1 g. The gas phase ( HCFC ) of the sample is removed 
at an ambient temperature using a gas phase recovery 
technique. Care should be exercised to retain liquid 
phase. 

The cylinder is then placed in a water bath at a 
temperature of SC'C and weighed periodically (15 min 
intervals ) until a stable weight recorded. 

The remaining liquid is used for determination of the 
percentage weight of the detoxifying component, a 
simple weighing technique being used. 

An additional gas chromatography should be 
performed on the resulting liquid at this stage to 
confirm that no HCFC remain in the sample. 



26.00 
19.80 



g 14.60 

E 



9.40 
4.20 i 



-1.00 




0.00 6.00 



Component Name 

F123 

X X 



12.00 



16.00 



TIME (min.) 



Retention Time [Min) 
2.100 
15.425 



24,00 



Area (%) 

5.480 
94.520 



30.00 



Fig. 6A Chrom-Card Strip-Chart of HCFC Blend A 



12 



0.00 



IS 15505 : 2004 




1400 



2800 



4200 



5600 



7000 



TIME (min.) 



Component Name Retention Time (M/n) Area (%) 

F22 1.333 85.249 

F124 3.333 9.758 

F123 6.083 4.994 

Fig. 6B Chrom-Card Strip-Chart of HCFC Blend A 



13